Field of the Invention
The present invention generally relates to a vehicle accessory power management assembly. More specifically, the present invention relates to a power transmitting device that changes the relative speed ratio between engine output and accessory input rotary power in response to a variety of vehicle related parameters.
Background Information
Vehicle power devices, such as internal combustion engines, typically provide rotary power to accessory devices, such as an air conditioning compressor, power steering and alternator, via a drive belt. An output shaft of the power device has a pulley that rotates with the output shaft, thereby moving the drive belt. The accessory devices also include respective pulleys connected to corresponding input shafts rotated by movement of the drive belt. In this drive belt arrangement, the rotational speed of the pulleys and input shafts of the accessory devices is directly related to the speed of the output shaft of the power device. If the power device is operating at a low RPM (revolutions per minute), the accessory devices are provided with rotary power at a corresponding low RPM. If the power device is operating at a high RPM, the accessory devices are provided with rotary power at a corresponding high RPM. However, there are circumstances where it is not necessary to provide an accessory device with high RPM power input while the power device is operating at a high RPM.